This invention relates to a turbo-molecular pump in which a rotor forming a pump is supported in a non-contact mode with the aid of a magnetic bearing.
Some turbo-molecular pumps of this type are provided with a heating system, namely, a heater, in order to eliminate a problem that compressed gas become coagulated and becomes stuck or accumulated on inside of the pump. In this case, in order to prevent the over-heating, a temperature detecting device is provided. A temperature adjusting unit, which controls the heater according to the output signal of the temperature detecting device, is provided in a pump control section which is adapted to control the magnetic bearing.
In the turbo-molecular pump having the heating system, since the pump control section has the temperature control unit, the pump control section is unavoidably bulky; that is, the resultant turbo-molecular pump has a high manufacturing cost.
Accordingly, an object of the invention is to solve the above-described problems. More specifically, an object of the invention is to provide a turbo-molecular pump in which, although it includes the heating system, the pump control section can be miniaturized and reduced in manufacturing cost, and which is therefore high in flexibility.
A turbo-molecular pump according to the invention is the one in which a rotor is supported by a magnetic bearing in a non-contact mode, and in which a pump control section has a digital operating system programmable using software or capable of executing a programmed software, the digital operating system performs the control of the heating system and at least part of the other controls. That is, the digital operating system performing the other controls, performs the control of the heating system.
As the digital operating system, a micro-computer, a digital signal operating processor, etc. can be used. In the specification, the digital signal operating processor (or digital signal processor) is dedicated hardware which is programable by a software or capable of executing programmed software, and achieves a high-speed time operation. Hereinafter, it will be referred to merely as a xe2x80x9cDSPxe2x80x9d, when applicable.
The pump control section has the digital operating system, so that the control of the heating system as well as the other controls is carried out thereby. Therefore, unlike the turbo molecular pump discussed in the xe2x80x9cBackground of the Inventionxe2x80x9d section, it is unnecessary to provide a temperature adjusting unit in the pump control section. This feature makes it possible to miniaturize the pump control section and to reduce the manufacturing cost. Furthermore, the control of the heating system can be freely designed with the software programs of the digital operating system; that is, the turbo-molecular pump of the invention is considerably high in the flexibility of use. In addition, the digital operating system can be utilized for various other purposes.
For instance, the digital operating system performs the control of the heating system, and at least the control of the magnetic bearing.
In this case, the digital operating system such as a DSP, which is provided in the pump control section to perform the control of the magnetic bearing, can be commonly used to perform the control of the heating system.
For instance, the digital operating system performs the control of the heating system and at least the control of the display system.
In this case, the digital operating system such as a micro-computer, which is provided in the pump control section to perform the control of the display system adapted to display a state of the pump, can be commonly used to control the heating system.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 9-194694 (filed on Jul. 22, 1997) and Hei. 10-192752 (filed on Jul. 8, 1998), which are expressly incorporated herein by reference in their entireties.